OP02.11: Intrapartum sonographic features of cephalopelvic disproportion in occiput anterior fetuses with protracted active phase of labour. Issue Volume 58:Issue S1(2021)Supplement (14th October 2021) - Dall'Asta, A.; Minopoli, M.; Cagninelli, G.; Sorrentino, S.; Corno, E.; Melandri, E.; Di Tonto, A.; Volpe, N.; Ghi, T.